Access sealing apparatus and method

ABSTRACT

A surgical access device includes a seal housing and a roller disposed in the housing and defining a working channel. The roller may be stationary or moveable within the seal housing to form both a zero seal in the absence of an instrument, and an instrument seal in the presence of an instrument. Rotation of the roller is contemplated and low-friction surfaces are discussed to reduce instrument insertion forces. Multiple rollers, wiper elements, low-friction braid, pivoting elements and idler rollers are contemplated. The rollers will typically be formed of a gel material in order to facilitate the desired compliance, stretchability and elongation desired.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/417,950, filed on Mar. 12, 2012, which is a continuation of U.S.patent application Ser. No. 12/791,607, filed on Jun. 1, 2010, now U.S.Pat. No. 8,157,835, which is a continuation of U.S. patent applicationSer. No. 10/776,387, filed on Feb. 10, 2004, now U.S. Pat. No.7,727,255, which is a continuation of International Application No.PCT/US2002/015696 filed on May 14, 2002, which published in English asInternational Patent Publication No. WO 2003/015848 A1 on Feb. 27, 2003,which claims the benefit of U.S. Application No. 60/312,683, filed onAug. 14, 2001, of which the entire disclosures are incorporated hereinby reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to access sealing devices and morespecifically to surgical devices and methods providing a working channelfor the insertion of instrumentation across a body wall and into a bodycavity.

2. Discussion of the Relevant Art

Access devices in general are disposed relative to a conduit and areadapted to provide input to a flow of fluid through the conduit. Thedevice will typically include a valve assembly which controls passage ofthe fluid in either a liquid state or a gas state. Such access devicesmight be adapted for use with fluids such as foods, oils, and grease,for example.

Devices of particular interest include surgical access devices which arecommonly used to form a passage way across a body wall and into a bodyconduit or other body cavity.

This passageway enables a surgeon operating exteriorly of the body toperform surgical operations within the body cavity by manipulatinginstruments through the passageway. These instruments might includescopes, needles, graspers, clamps, staplers, sutures, and cutters, forexample.

Of course the passageway, more commonly referred to as a workingchannel, also provides a path for fluids to exit the body from the bodycavity. In order to inhibit this leakage of fluids, some access devicesare provided with valves which can seal the working channel both in theabsence of an instrument and in the presence of an instrument.

The sealing of the working channel is of particular importance in thecase of laparoscopic surgeries where the abdominal cavity is inflatedwith an insufflation gas in order to distend the abdominal wall andthereby increase the size of the working environment. Trocars arecommonly used as access devices for this type of surgery. The trocarsinclude a cannula and a seal housing containing one or more valves whichfacilitate instrument access while inhibiting leakage of theinsufflation gas.

In the past, trocar valves have typically included at least one zerovalve intended to form a zero seal in the absence of an instrument, andat least one instrument valve intended to form an instrument seal in thepresence of an instrument. Zero seals have typically been formed byduckbill seals which are incapable of also functioning as an instrumentseal. The instrument seals have typically been formed by septum valves,having a hole or opening which is radially stretchable to some limitedextent. With the limited stretchability of the septum valves, thetrocars of the past have been able to accommodate only a small range ofinstrument diameters.

Due to this limited accommodation of instrument sizes, different trocarshave been required in order to accommodate a full range of instrumentsizes from almost zero mm to 12 mm. In some cases a smaller trocar wouldbe used initially only to find that a larger instrument was required. Inthese instances, the smaller trocar had to be completely removed inorder to inset a larger trocar to accommodate the larger instrument. Asa result, a whole set of trocars, each having a different septum valvewere required. Eventually, single trocars were provided having multipleseptum valves of different sizes, along with a zero valve for each ofthe septum valves. Of course these instruments were much more complexand expensive.

In the past, septum valves were positioned along the axis of the workingchannel. However, it was observed that instrument seals would tend toleak if the instrument was moved off-axis. Accordingly, septum valveswere provided with floating characteristics whereby the seal interfacecould be maintained even if the instrument was positioned off-axis. Ofcourse, this floating of the septum seal required special structurewhich increased the cost of manufacture.

Septum valves have also been highly susceptible to tearing, particularlyby instruments having sharp points. Elaborate guiding and protectionmechanisms were provided to protect the septum seals against this typeof instrument. Again, the sophisticated protection structuressignificantly increased the complexity of the device and the resultingcost of manufacture.

SUMMARY OF THE INVENTION

These deficiencies of the past are overcome with the present inventionwhich includes a seal material in the form of a gel. The gel is highlycompliant and stretchable. As a result of these properties, a singlevalve can function not only as a zero seal, but also as an instrumentseal capable of accommodating the full range of instrument sizes. Theincreased compliance and stretchability of the gel material easilyaccommodates instruments which are moved off-axis, so no additionalfloating structure is required.

In a preferred embodiment, the valve is provided in the form of a rollerhaving an axle supported by the seal housing. The valve can be rotatableon an axle having a fixed relationship with the seal housing or thevalve can be rotatable with the axle relative to the seal housing.

In one aspect of the invention, a trocar is adapted to provide accessfor a surgical instrument through a body wall and into a body cavity.The trocar includes a cannula having a proximal end and a distal end,and a seal housing disposed at the proximal end of the cannula anddefining with the cannula a working channel. A seal assembly is disposedwithin the housing and includes at least one roller, having an axissupported by the seal housing. The roller has properties for forming azero seal in the absence of the instrument, and an instrument seal inthe presence of the instrument.

In another aspect of the invention, a surgical combination includes aninstrument having a diameter of at least five millimeters, and an accessdevice adapted to facilitate disposition of the instrument across thebody wall. A cannula is included in the access device along with a sealhousing which forms a working channel with the cannula. A seal assemblyis disposed in the housing and includes a roller sized and configured toform a zero seal in the absence of the instrument and an instrument sealin the presence of the instrument.

In an additional aspect of the invention, a trocar assembly includes acannula having a proximal end and a distal end, a seal housing isdisposed at the proximal end of the cannula and forms a working channelwith the cannula. A roller is disposed in the seal housing and ispivotal on an axis. A resilient material included in the roller hasproperties susceptible to tearing in response to an instrument insertedinto the working channel. The roller is moveable by the insertedinstrument to pivot the resilient material relative to the axis andthereby inhibit tearing of the resilient material.

In a further aspect of the invention, the trocar assembly includes aroller having an outer surface pivotal on an axis and disposed inproximity to an inner surface of the seal housing. At least one wiper isdisposed between the outer surface of the roller and the inner surfaceof the housing.

In an additional aspect of the invention, the trocar assembly includes aroller having an axle supported by the seal housing. The roller hasproperties for forming an instrument seal when the instrument isinserted into the working channel. A resilient material defines an outersurface of the roller, and portions of one of the resilient material andthe axle define at least one void.

In another aspect of the invention, the trocar assembly includes aroller having a resilient outer surface and an axle for pivoting theouter surface relative to the inner surface of the seal housing.Portions of the inner surface of the seal housing define at least onerecess configured and arranged to receive the axle.

The trocar assembly in a further aspect of the invention includes avalve disposed in the valve housing and formed of a compliant material.The valve has properties for forming a zero seal across the workingchannel in the absence of the instrument and an instrument seal acrossthe working channel in the presence of the instrument. The instrumentseal has a diameter in radial cross-section ranging from a lower limitof about zero millimeters to an upper limit in a range between about sixmillimeters and about 12 millimeters.

In still a further aspect of the invention, a trocar assembly includes avalve disclosed in the valve housing. The valve is moveable within thevalve housing between a first position wherein the valve has firstcompression characteristics relative to the instrument, and a secondposition wherein the valve has second compression characteristicsrelative to the instrument. The housing includes a pair of opposingwalls which diverge between the first position and the second position.The housing in axial cross-section has a triangular or trapezoidalconfiguration.

These and other features and advantages of the invention will becomemore apparent with a discussion of preferred embodiments in reference tothe associated drawings.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a laparoscopic surgery with asurgical instrument in the form of a grasper inserted through a workingchannel of a trocar of the present invention;

FIG. 2 is a side elevation view of the trocar illustrated in FIG. 1;

FIG. 3 is an axial cross-section view taken along lines III-III of FIG.2;

FIG. 4A is a radial cross-section view taken along lines IVA-IVA of FIG.3;

FIG. 4B is an axial cross section view taken along lines IVB-IVB of FIG.4A;

FIG. 5 is a cross-section view similar to FIG. 3 and illustrating a pairof low-friction washers in another embodiment of the invention;

FIG. 6 is a perspective view of a gel roller adapted for use in thetrocar of FIG. 1;

FIG. 7 is an axial cross-section view taken along lines VII-VII of FIG.6;

FIG. 8 is an axial cross-section view similar to FIG. 3 with the rollersremoved to show axle recesses;

FIG. 9 is an axial cross-section view similar to FIG. 8 and showing axlerecesses with an oblong, vertical orientation;

FIG. 10 is an axial cross-section view similar to FIG. 8 andillustrating a pair of rollers each with axles oblong in cross-section;

FIG. 11 is an axial cross-section view similar to FIG. 8 andillustrating rollers with a pair of axially oriented in-line axles;

FIG. 12 is an axial cross-section view similar to FIG. 8 and showingin-line axles with a radial orientation;

FIG. 13A is an axial cross-section view similar to FIG. 8 andillustrating rollers with oblong axles pivotal with respect to theworking channel of the trocar;

FIG. 13B is a cross-section view taken along lines XIIIB-XIIIB of FIG.13A;

FIG. 14 is an axial cross-section view similar to FIG. 8 andillustrating rollers with radially-spaced axles;

FIG. 15A is an axial cross-section view similar to FIG. 8 andillustrating a convex protrusion disposed between axle recesses;

FIG. 15B is a cross-section view taken along lines XVB-XVB of FIG. 15A;

FIG. 16 is an axial cross-section view similar to FIG. 7 andillustrating a roller with an axis and an axle having a springconfiguration;

FIG. 17 is an axial cross-section view similar to FIG. 16 andillustrating an axle with an irregular outer surface forming a concaveannulus;

FIG. 18 is an axial cross-section view similar to FIG. 17 wherein theirregular surface on the axle comprises at least one convex annulus;

FIG. 19 is a cross-section view similar to FIG. 17 wherein the irregularsurface is formed by rotating at least one straight line about the axis;

FIG. 20 is an axial cross-section view similar to FIG. 17, wherein theirregular surface of the axle is formed with both concave and convexsurfaces, and the gel roller is formed with a circumferential slit whichextend radially to the axle;

FIG. 21 is a cross-section view similar to FIG. 20 wherein thecircumferential slits are terminated short of the axle;

FIG. 22 is an axial cross-section view wherein the gel roller has acircumferential groove;

FIG. 23 is an axial cross-section view similar to FIG. 3 wherein the gelof the rollers is formed with multiple voids;

FIG. 24 is an axial cross-section view similar to FIG. 17 wherein theaxle includes holes configured to receive a portion of the gel materialforming the roller;

FIG. 25 is an axial cross-section view similar to FIG. 24 wherein therollers are formed without axles;

FIG. 26 is an axial cross-section view similar to FIG. 24 wherein therollers in the radial cross-section have the shape of a star;

FIG. 27 is an axial cross-section view similar to FIG. 24 wherein therollers are formed as inflated bladders;

FIG. 28 is an axial cross-section view similar to FIG. 3 wherein therollers are provided with wiper elements;

FIG. 29 is an axial cross-section view similar to FIG. 28 wherein theseal housing is provided with wiper elements;

FIG. 30 is an axial cross-section view similar to FIG. 29 wherein thewiper elements of the housing form a reservoir;

FIG. 31 is an axial cross-section view similar to FIG. 29 wherein thehousing wiper elements define a portion of the working channel;

FIG. 32 is an axial cross-section view similar to FIG. 31 wherein thehousing wiper elements define the working channel both proximally anddistally of the rollers.

FIG. 33 an axial cross-section view similar to FIG. 3 with four rollersforming multiple reservoirs;

FIG. 34-35 illustrate an embodiment wherein the rollers are positionedradially and are pivotal on a floating ring axle;

FIG. 34 is an axial cross-section view similar to FIG. 3 and showing twoof the radially positioned rollers;

FIG. 35 is a radial cross-section view of the radially spaced rollerseals taken along lines XXXV-XXXV of FIG. 34;

FIG. 36 is an axial cross-section view showing the roller with atoroidal configuration;

FIG. 37 is a cross-section view of the toroidal roller taken along linesXXXVII-XXXVII of FIG. 36;

FIG. 38 is an axial cross-section view of an additional embodimentincluding idler rollers;

FIG. 39 is an axial cross-section view similar to FIG. 3 wherein theaxles of the rollers are pivotal relative to the housing;

FIG. 40 is an axial cross-section view similar to FIG. 3 and includingthree rollers defining two working channels;

FIG. 41 is an axial cross-section view similar to FIG. 3 wherein asingle roller forms a zero seal with a wall of the housing;

FIG. 42 is an axial cross-section view similar to FIG. 3 wherein theseals in the housing are formed by non-rotatable elements;

FIG. 43 is an axial cross-section view similar to FIG. 3 wherein thezero seal in the housing is facilitated with a spring-biased roller;

FIG. 44 is an axial cross-section view similar to FIG. 31 with a singleroller pivotal relative on the housing;

FIG. 45 is an axial cross-section view similar to FIG. 44 and includingtwo opposing rollers pivotal on the housing;

FIG. 46 is an axial cross-section view similar to FIG. 3 includingpivoting levers which extend from the seal housing to engage the roller;

FIG. 47 is an axial cross-section view similar to FIG. 3 wherein theworking channel through the seal housing is lined with a tubular braid;

FIG. 48 is an axial cross-section view similar to FIG. 3 wherein therollers are covered with braid or fabric sleeves;

FIGS. 49-50 illustrate a roller valve in a seal housing adapted for useto facilitate fluid flow from an inlet to an outlet of the housing;

FIG. 49 is an axial cross-section view showing the rollers engaging eachother in the seal housing in response to fluid back pressure;

FIG. 50 is an axial cross-section view similar to FIG. 49 showingdeformation of the seals to create a fluid passageway in response tofluid forward pressure;

FIG. 51 is an axial cross-section view of a further embodiment whereinrollers are combined with a circumferential balloon element to form acatheter adapted for use within a body conduit;

FIG. 52 is an axial cross-section view of a catheter having rollers atits distal end;

FIG. 53 is an axial cross-section view of an embodiment including ashaft and a pair of rollers moveable within the shaft to form aninstrument seal with a suture;

FIGS. 54-55 illustrate an embodiment similar to that of FIG. 35 whereinthe rollers are disposed in an associated quadrant of the seal housing;

FIG. 54 is an axial cross-section view similar to FIG. 34;

FIG. 55 is a cross-section view of the rollers seals taken along linesLV-LV of FIG. 54;

FIG. 56 is a perspective view of an embodiment wherein the seal housinghas a triangular or trapezoidal configuration with a narrow proximal endand a wide distal end;

FIG. 57 is a perspective view similar to FIG. 56 showing seal elementsat the proximal end of the housing in response to insertion of a smallinstrument;

FIG. 58 is a perspective view similar to FIG. 57 illustrating the sealelements stretched toward a distal end of the housing in response toinsertion of a large instrument;

FIG. 59 is a top plan view of the seal housing in FIG. 56;

FIG. 60 is a top plan view of the seal housing in FIG. 57;

FIG. 61 is a top plan view of the seal housing in FIG. 58; and

FIG. 62 is a top plan view similar to FIG. 59 and illustrating rollingendless loops of low-friction material disposed between the sealelements and the sidewalls of the housing.

DESCRIPTION OF PREFERRED EMBODIMENTS AND BEST MODE OF THE INVENTION

A trocar is illustrated in FIG. 1 and designated by the referencenumeral 10. The trocar 10 is operatively disposed to provide accessacross a body wall, such as the abdominal wall 12, and into a bodyconduit or cavity, such as the abdominal cavity 14. In this case, thetrocar 10 is representative of any access device which extends across abody wall to provide access into a body conduit or cavity. The accessdevice may facilitate a flow of fluids, either gas or liquid, into orout of the conduit or cavity 14. Alternatively, the access device mayaccommodate a surgical instrument, such as a needle, which can beinserted through the access device and into the body conduit or cavity14.

In the illustrated embodiment, the trocar 10 includes a cannula 16 whichextends along an axis 18 between a proximal end 21 and a distal end 23.A seal housing 25 is disposed at one of the proximal end 21 and thedistal end 23 of the cannula 16, and forms with the cannula 16, anaccess or working channel 27. This working channel is sized andconfigured to receive a surgical instrument 30, such as a grasper, whichwill typically include an elongate tube or shaft 32 having a maximumdimension or diameter, shown by arrows 34.

In this case, the grasper or instrument 30 is representative of anysurgical instrument or device which might be inserted through theworking channel 27 of the trocar 10 and into the body cavity, such asthe abdominal cavity 14. Other instruments may be as small as a suture(not shown) which might have a diameter less than one millimeter, aswell as scopes, cutters, clip appliers, clamps and even staplers, whichmight have a diameter as large as 12 millimeters.

In general, it may be desirable that the access device, such as thetrocar 10, have properties for inhibiting the egress of fluids outwardlythrough the working channel 27. This is particularly important in thecase of laparoscopic surgeries where the abdominal cavity 14 istypically inflated with a gas in order to elevate the abdominal wall 12and thereby increase the volume of the working environment. The sealingof the working channel 27 is of course complicated by the desire tointroduce instruments, such as the grasper, along the working channel27. Not only is sealing of the working channel 27 desired in the absenceof the instrument 30, but it is also desired when the instrument 30 isoperatively disposed as illustrated in FIG. 1.

A seal assembly 36 of the present invention is illustrated in the axialcross-section view of FIG. 3. This seal assembly includes two rollers 38and 41, having axles 43 and 45, respectively. The rollers 38 and 41 arerotatable on respective axes and relative to an inner surface 47 of theseal housing 25. The axles 43 and 45 may be rotatable with therespective rollers 38 and 41 relative to the housing 25, or may be fixedto the seal housing 25 in which case the rollers 38 and 41 also rotaterelative to their respective axles 43 and 45.

In the embodiment of FIG. 3, the rollers 38 and 41 each have acylindrical outer surface as well as a pair of end surfaces. Forexample, the roller 38 has a cylindrical outer surface 50 bestillustrated in FIG. 3, as well as a pair of end surfaces 52 and 54, bestillustrated in FIG. 4A. The roller 41 is similarly constructed with acylindrical outer surface 56 and a pair of end surfaces 58 and 61.

In order to form the desired seals across the working channel 27, it isimportant that the rollers 38 and 41 form each lateral seals and endseals with the inner surface 47 of housing 25. Thus, in a preferredembodiment, lateral seals 63 and 65 are formed between the seal housing25 and the respective cylindrical surfaces 50 and 56. Similarly, endseals are formed between the seal housing 25 and the end surfaces ofeach of the rollers 38 and 41. For example, end seal 67 and 70 areformed between the seal housing 25 and the end surfaces 52 and 54 of theroller 38. Similar end seals 72 and 74 are formed between the sealhousing 25 and the end surfaces 58 and 61 of the roller 41. Incombination, the lateral seals 63, 65 and the end seals 67-74 form acontinuous seal between the seal assembly 36 and the seal housing 25.Importantly, the rollers 38 and 41 also form a zero seal 76 or aninstrument seal 78 which are necessary to close the working channel 27both in the absence of the instrument 30 and in the presence of theinstrument 30, respectively.

In the illustrated embodiment, the zero seal 76 is formed between therollers 38 and 41 in the absence of the instrument 30. Collectively, thelateral seals 63, 65, the end seal 67-74, and the zero seal 76 close offor seal the working channel 27 in the absence of the instrument 30.

When the instrument 30, such as the grasper, is inserted into the trocar10, as illustrated in FIG. 1, the instrument seal 78 is formed betweenthe shaft 32 and the rollers 38, 41. Collectively, the lateral seal63-65, the end seals 67-74, and the instrument seal 78 close off or sealthe working channel 27 in the presence of the instrument 30.

Given the desire to form the various seals including the lateral seals,the end seals, the zero seal, and the instrument seal, it can beappreciated that a special material is required for the rollers 38 and41. A material of particular interest is that disclosed by applicant inco-pending U.S. Patent Application Ser. No. 60/241,958 filed on Oct. 19,2000, entitled “Hand-Assisted Laparoscopy Apparatus and Method,” whichis incorporated herein by reference. This particular material is a gelmaterial 80 which has properties including a low durometer hardness anda high tear strength. In addition, the gel material 80 tends to havefloat characteristics similar to a fluid in that it is easily displaced,for example, by insertion of an instrument, without affecting theinstrument seal. Although the gel has characteristics of a fluid, italso has characteristics of a solid in that it can be formed, forexample, molded to a desired shape.

Various coatings or lubricants can be applied to the sealing surfaces ofthe rollers 38 and 41 to facilitate formation of the various seals.

Given these characteristics, the gel material of the rollers 38 and 41can easily form the zero seal 76, and upon insertion of the instrument30, easily form the instrument seal 78. Importantly, the instrument seal78 can accommodate a wide range of instrument diameters. For example, asuture having a diameter of only about one millimeter can be easilyaccommodated by the rollers 38 and 41. And when a large instrumenthaving a diameter such as 12-15 millimeters, is inserted, the instrumentseal 76 can compliantly expand to accommodate the larger diameter. As aresult, the single trocar 10, having but a single valve formed by therollers 38 and 41, can accomplish all of the sealing desired whether inthe absence of the instrument 30 or in the presence of the instrument30, and regardless of instrument diameters.

These advantages can accrue to any embodiment merely having a geldisposed within the seal housing 25. In the illustrated embodiment, itis the gel material 80 and its float characteristics which form thehighly complaint instrument seal capable of accommodating a wide rangeof diameters. Forming this gel material 80 into a roller, such as therollers 38 and 41, adds the further advantage of protecting the gelmaterial against any tendency to tear or propagate due to insertion of asharp instrument. With the roller configuration, a sharp point engagingthe outer surface of the roller 38, for example, will cause the roller38 or 41 to rotate on its axis and ultimately disengage the sharpinstrument point without tearing the gel material 80. A furtheradvantage of having two of the rollers 38, 41, is that the instrument 30tends to be centered along the axis 18 within the working channel 27.Also, with two cylindrical rollers, more than one instrument may beinserted at the same time, in which case two of the instrument seals 78are formed. For example, if a grasper is used to insert a suture,instrument seals 78 are formed around each of the grasper and thesuture.

Providing the rollers 38 and 41 with an ability to move or rotaterelative to their axes, facilitates the introduction of an instrument bychanging a frictional resistance to a rolling resistance at theinstrument seal 78. Of course, as the rollers 38 and 41 rotate,frictional resistance is encountered at the lateral seals 63 and 65 aswell as the end seals 67-74. This frictional resistance can be reducedby providing the inner surface 47 of the housing 25 with a low frictioncoating. Alternatively, pockets of lubricating material, discussed ingreater detail below, can be formed to reduce the friction associatedwith these seals. Friction at the end seals 67-74 can also be addressedby providing low-friction washers, such as those designated by thereference numerals 81 and 83 in FIG. 5. These washers can be centered onthe axles 43 and 45 of the rollers 38 and 41, respectively, so that theend seals 67-74 can be maintained with a reduced friction on the rollers38 and 41. The washers 81 and 83 can be made of apolytetrafluoroethylene material or alternatively can be formed of afabric material.

The individual rollers 38 and 41 and their associated axles 43 and 45,respectively, can be formed as illustrated in FIGS. 6 and 7. Forexample, the axles 43 and 45 can be formed of a rigid plastic with thegel material 80 molded to the axle 43. The cylindrical outer surface 56,as well as the end surfaces 61 and 63, of the roller 38 are alsoillustrated in FIGS. 6 and 7.

In the illustration of FIG. 8, the rollers 38 and 41 are not shown inorder to illustrate axle recesses 85 and 87 which can be formed on eachof the end walls associated with the housing 25. These recesses 85 and87 can be sized and configured to rotatably receive the axles 43 and 45.The recesses 85, 87 most easily accommodate an embodiment wherein thegel material 80 and the associated axle, such as the axle 43, have afixed relationship. In such an embodiment, the axle 43 is supportedwithin the recess 85, and the entire roller, including the axle 43 andgel material 80, rotates relative to the housing 25.

In the embodiment of FIG. 9, the recesses 85 and 87 are formed with anoblong configuration in radial cross section. The recess 85, forexample, has a length and a width and the length is oriented generallyparallel to the axis 18. In such an embodiment, the axle 43 of theroller 38 would be disposed in the recess 85. With its elongateconfiguration, the recess 85 would accommodate both rotation andtranslation of the roller 38. Thus, the axle 43 might be biased towardthe proximal end of the recess 85 but permitted to rotate and translatedistally with insertion of an instrument. The translation offered bythis embodiment would tend to reduce the insertion forces on theinstrument 30.

The oblong recesses 85 and 87 could also accommodate axles 90 and 92that are oblong and cross section as illustrated in FIG. 10. With thelength of the oblong cross section oriented generally parallel to theaxis 18, greater axial support is provided for the roller 38. Thisorientation also reduces the transverse axle 90 in order to accommodatelarger instruments between the two axles 90 and 92. The oblong axles 90and 92 would typically have a fixed relationship with the housing 21, sothe gel material 80 would rotate about the axle 90 and 92 in thisembodiment. Translation could be provided by recesses 85 and 87 having agreater length than that of the axle cross-section.

In a further embodiment of the invention illustrated in FIG. 11, therollers 38 and 41 are each formed with a pair of in-line axles. Forexample, the roller 38 includes cylindrical axles 94 and 96 which may berotatable within a common oblong recess, such the recess 85. The axles94 and 96 in the illustrated embodiment are aligned longitudinally orgenerally parallel to the axis 18. The gel material 80 in thisparticular embodiment is rotatable relative to the axles 94 and 96 whichare in turn rotatable with respect to the seal housing 25. With thisconfiguration, the in-line axles 94, 96 function as needle bearingsrotatably supporting the gel material 80 which functions as a conveyorbelt. This construction tends to further reduce insertion forcesencountered by the instrument 30. Of course the in-line axles 94 and 96could be oriented laterally of each other as illustrated in FIG. 12, orgenerally disposed, at any other angle relative to the axis 18.

In the embodiment of FIG. 13A, the rollers 38 and 41 are mounted onaxles 98 and 101, respectively, having an oblong configuration. In thiscase, the axle 98, for example, is provided with a cylindrical mountingpin 103 which is sized and configured to be received in the associatedrecess 85. With the pin 103 disposed at one end of the oblongcross-section, as shown in FIG. 13B, the roller 38 will tend to pivot,perhaps against a spring bias, as the instrument is inserted. In thiscase, translation of the roller 30 is along an arc shown generally bythe arrow 105 in FIG. 13A.

The structure of FIG. 14 is similar to that of FIG. 11 in that therollers 38 and 41 are provided with multiple axles. In this embodiment,for example, the roller 38 has four axles, 103, 105, 107 and 110 whichare rotatable on individual axes, and also revolve about a common lineshown as a point 112 in FIG. 14. With the gel material 80 of the roller38 provided with a cylindrical inner hole 113, its rotation, is greatlyfacilitated by the multiple axles 103-110 which function as needlebearings.

The embodiment of FIG. 15A is similar to that of those previouslydiscussed except that this embodiment includes a protrusion 114 whichextends inwardly of the seal housing 25. In the illustrated embodiment,the protrusion 114 is disposed between the recesses 85 and 87 and has aconvex configuration. With an opposing protrusion 116 extending inwardlyfrom the opposite wall as shown in FIG. 15B, the protrusions 114 and 116function to center the instrument 30 along the rollers 38 and 41, whichfor clarity are not shown in this view. The convex protrusions 114 and116 also serve to add additional compression on the end surfaces of therollers in order to aid in sealing around the inserted instrument 30.

A preferred embodiment of the roller 38 was described with references toFIGS. 6 and 7. Many other embodiments of the roller 38 will now beapparent to those of ordinary skill in the art. These additional rollerembodiments will typically be formed with a fixed relationship betweenthe axle 43 and the gel material 80. Nevertheless, as previously noted,the roller 38 can be formed with the axle 43 maintained in a fixedrelationship with the seal housing 25. In this latter case, the gelmaterial 80 would typically revolve about the fixed axle 43.

One of the additional roller embodiments is illustrated in FIG. 16 wherethe axle 43 is formed as a spring. With this configuration, the axle isslightly bendable or deformable along its length, thereby aiding in theability of the roller 38 to conform to the shape of inserted instrument30 such as the grasper.

Another roller embodiment is illustrated in FIG. 17 wherein the axle 43has a shape other than the cylindrical shape illustrated in theembodiment of FIG. 7. In this case, the axle 43 has an angular groove118 which is disposed within the gel material 80. This groove 118facilitates orientation of the gel material 80 relative to the axle 43.Particularly in an embodiment wherein the gel material 80 revolvesaround a fixed axle 43, the groove 118 facilitates a preferreddisposition of the gel material 80 centered on the axle 43.

With reference to FIG. 18, it can be appreciated that the centeredrelationship between the gel material 80 and the axle 43 can actually befacilitated by angular protrusions designated by the reference numeral121. These protrusions 121 can be formed as a surface of revolutiondefined by multiple semi-circles as illustrated in FIG. 18.Alternatively, the protrusions 121 might be formed as surfaces ofrevolution defined by straight lines, perhaps forming peaks and valleysas illustrated in the embodiment of FIG. 19.

In the embodiment of FIG. 20, the axle 43 is similar to that of FIG. 17in that it includes an angular groove 118. It is also similar to theembodiment of FIG. 18 in that it includes protrusions 121. In each ofthe embodiments disclosed in FIG. 17-20, the non-cylindrical shape ofthe axle 43 serves to circumferentially compress the gel material 80around any inserted instrument 30 to facilitate sealing and minimize anytendency toward a “cat-eye” effect

In the embodiment of FIG. 20 the gel material 80 is formed with at leastone groove 123 which begins at the cylindrical surface 56 and extendsinwardly toward the axle 43. It is the purpose of the groove 123 tofacilitate compliance of the gel material 80 with the instrument 30.This enhances formation of the instrument seal 78 by dividing the gelmaterial into discreet sections 125 and 127. Of course these sectionscan be defined by any groove extending inwardly from a surface of thegel material 80. The groove 123 need not be planar, but can have acurved or rounded configuration. It can also be disposed at any anglewith respect to the axle 43, not just the 90-degree angle illustrated inFIG. 20.

The groove 123 can have a constant width or even a variable width indifferent embodiments. The groove 123 can extend from the cylindricalsurface 56 to the axle 43, as illustrated in FIG. 20, or can extend onlya portion of this distance as illustrated in FIG. 21. It can also beformed as a surface of revolution about the axis 18. For example, inFIG. 22, this surface of revolution is defined by a semi-circle 125.

Grooves such as the groove 123, which facilitates compliance of the gelmaterial 80 with the instrument 30, can also be formed interiorly of thegel material 80 as illustrated by the voids 127 in FIG. 23. These voids127 also create space into which the gel material can more easily flowto provide the desired compliance characteristics. The voids 127 cantake generally any shape, not just the cylindrical shape illustrated inthe cross-sectional view of FIG. 23. The gel voids 127 can extend to asurface of the gel material 80 or be defined entirely within the gelmaterial 80.

Voids can also be created in the axle 43, but for a entire differentpurpose. Such voids are illustrated in FIG. 24 and designated by thereference numeral 130. The purpose of these voids 130 is to facilitate aflow of the gel material into the voids 130 as the gel material 80 isinsert molded onto the axle 43. With the gel 80 extending outwardly ofthe axle 43 and through the voids 130 of the axle 43, the fixedrelationship between these two structures is greatly facilitated.

In other embodiments, the gel material 80 can be formed into a pluralityof independent structures 132 and 134 which may either have a fixedrelationship or a moveable relationship with respect to the seal housing25. In embodiments wherein the structures 132 and 134 are moveable, theabsence of axles could facilitate movement of the structures 132 and 134in an independent and random manner. Such movement might include bothrotational movement, as well as translational movement. Although the gelstructures 132 and 134 and FIG. 25 are illustrated to have a cylindricalconfiguration, it will be apparent that the number and shape of thevarious gel structures 132, 134 may vary considerably in differentembodiments of the invention.

The outer surface of the gel material 80 can also have many differentforms as illustrated by the embodiment of FIG. 26. In thiscross-sectional view, the rollers 38 and 41 have an outer surfacedefined by alternating peaks and valleys. In the cross-section view,these rollers 38, 41 have the configuration of a star and are orientedwith respect to each other so that the peaks of each roller 38, 41 alignwith the valleys of the opposing roller 41, 38 in a mesh-gearconfiguration.

FIG. 27 illustrates an embodiment wherein the rollers 38 and 41 areconfigured as inflatable bladders 132 and 134. The bladder 132 willtypically be formed as a cylinder having an outer skin 136 supported atits ends on the axle 43. This skin 136 defines an interior cavity whichcan be inflated, typically with an inflating material 138 which may befluid or semi-fluid such as a gas or liquid. Thus inflated, the bladder132 is provided with characteristics which are highly compliant andtherefore beneficial to the formation of the instrument seal 78. Theskin 136 can be formed from a gel of the type previously disclosed orcan be formed from a less compliant material. Particularly with therolling characteristics, this embodiment will not be particularlysusceptible to puncture.

A further embodiment of the invention is illustrated in FIG. 28 whereinthe rollers 38 and 41 are illustrated to include wiper seals 140 and143, respectively. These wiper seals 140, 143 extend outwardly from thecylindrical surface 56 toward the inner surface of the seal housing 25.As the rollers 38 and 41 revolve about their respective axles 43 and 45,at least one of the wipers 141 and at least one of the wipers 143,respectively, form the lateral seals 63, 65 and end seals 67-74 with thehousing 25. With a reduced area of contact between the wipers 141, 143and the seal housing 125, there is a decrease in the frictionalresistance associated with rotation of the rollers 38 and 41. Reducedfrictional resistance is desirable as it decreases instrument insertionforces.

In the embodiment of FIG. 29, this reduced frictional resistanceassociated with the lateral seal 63 and 65 is maintained with astructure wherein the seal housing 25 is formed with wipers 141 and 147that extend inwardly to contact the cylindrical surfaces 50 and 56 ofthe rollers 38 and 41, respectively. With the wipers 141 and 147 havinga stationary or fixed relationship with the housing 25, they also definewith the rollers 38 and 41 a pocket 152 which can be filled with a fluidor semi-fluid material 154 such as a lubricant or antiseptic. Thismaterial is initially maintained in the pocket 152 but ultimately coatsthe rollers 138, 141 as they rotate in response to insertion of theinstrument 30.

Multiple pockets, such as the pocket 152 can be formed by providingadditional wipers 156 and 158 as illustrated in FIG. 30. In this case, apocket 161 is formed between the wipers 141 and 156, while a pocket 163is formed between the wipers 143 and 158. Different materials can bedisposed in the different pockets 161, 163.

In the embodiments of FIGS. 29 and 30, the stationary wipers 141, 143extend laterally, transverse to the axis 18. In the embodiment of FIG.31, these wipers 141 and 143 extend axially from the seal housing 25into contact with the cylindrical surfaces 50 and 56, respectively. Withthis configuration, the wipers 141, 143 also function as guides tofacilitate introduction of the instrument 30 directly between therollers 38 and 41.

With reference to the embodiment of FIG. 32, it will be appreciated thatthe stationary wipers 156 and 158 can also be oriented axially tofacilitate formation of the pockets 161, 163 and to function further asguiding elements for the instrument 30.

Additional sealed pockets 165 and 170 can be formed in an embodimentincluding not only the rollers 38, 41, but two additional rollers 172and 174. Such an embodiment is illustrated in FIG. 33.

The embodiment illustrated in FIG. 34 is most easily distinguished withreference to the cross-section of view of FIG. 35. In this embodiment,the gel material 80 is formed in multiple sections 181-186 which arepositioned radially of the axis 18 and collectively form a toroid 190.The sections 181-186 are individually rotatable about a common axle 192which also has a toroidal configuration. It will be noted that in thisembodiment the zero seal 76, as well as the instrument seal 78, areformed interiorly of the toroidal axle 192. Maintaining the rotationalcharacteristics of the individual sections 181-186 also facilitatesinsertion of the instrument 30 into the working channel 27.

With the gel material 80 in a toroidal configuration, it is particularlyadvantageous to form the seal housing 25 with a cross section that iscircular as illustrated in FIG. 35. This circular cross section would beexhibited with the seal housing 25 having a conical or cylindricalconfiguration. The circular cross section is desirable since thetoroidal gel material 80 is also circular on its outer edge. Thisfacilitates formation of a single continuous seal between the housing 25and the gel material 80. Thus, with the circular cross section, for thehousing 25 and the toroidal configuration for the gel material 80, allseals necessary to seal the working channel both in the presence and inthe absence of the instrument 30, are formed by the gel material 80.This configuration also greatly facilitates the manufacturing processwhere the toroidal gel material 80 is merely inserted into the conicalor cylindrical seal housing 25.

These same characteristics are exhibited in a further embodiment, whichis illustrated in FIG. 36 and the cross-sectional view of FIG. 37. Inthis case, the various sections 181-186 associated with the embodimentof FIG. 35 are formed in an integral configuration so that the toroid190 rotates as a single unit around the toroidal axle 192. Thisembodiment is less expensive to manufacture but still maintains theadvantages associated with the toroidal configuration.

FIG. 38 illustrates another embodiment which is similar to that of FIG.29 except that the wipers 141 and 147 of that embodiment are replacedwith idler rollers 194 and 196. These idler rollers 194, 196 can besupported on the seal housing 25 where they are permitted to rotate ontheir respective axes. The idler rollers 194 and 196 provide the lateralseals 63 and 65 between the seal housing 25 and the rollers 38 and 41,respectively. By including the idler rollers 194, 196, frictionalresistance associated with the embodiment of FIG. 29 is replaced with areduced rotational resistance, thereby facilitating insertion of theinstrument 30.

Other embodiments of the invention are associated with variousstructures for mounting the axles 43 and 45 relative to the seal housing25. In the embodiment of FIG. 39, these axles 43 and 45 are mounted onsupports 198 and 201 which are in turn pivotally supported by the sealhousing 25. The supports 198 and 201 can be spring biased to move therollers 38 and 41, respectively, toward each other. This bias willfacilitate formation of both the zero seal 76 and instrument seal 78.

Two entry ports, 203 and 205, are provided in the embodiment of FIG. 40which also includes a third roller 207 disposed between the rollers 38and 41. With this structure, two valves 210 and 212 are formed, onebetween the rollers 38 and 207 and the other between the rollers 41 and207. In the absence of any instrument 30, the valves 210 and 212 willform zero seals across the associated ports 203 and 205. When aninstrument is inserted into the entry port 203, an instrument seal willbe formed by the valve 210. Similarly, an instrument inserted into theentry port 205 will form an instrument seal with the valve 212. Ofcourse rotation of the valves 38, 41 and 207 will vary greatly dependingon the timing of instrument introduction and removal.

The embodiment of FIG. 41 is interesting as it illustrates that only thesingle roller 38 may be required to form both the zero seal 76 andinstrument seal 78. In the illustrated embodiment, an interior wall 214extends inwardly from the seal housing 25 toward the axis 18 and forms asealing valve 216 with the roller 38. Thus, the sealing valve 216 formsthe zero seal 76 between the wall 214 and the roller 38 in the absenceof the instrument 30. When the instrument 30 is inserted, the instrumentseal 78 is formed between the wall 214 and the roller 38.

In FIG. 42, a sealing valve is formed between the rollers 38 and 41 asin previous embodiments. Although these rollers 38 and 41 are formed onthe axles 43 and 45, respectively, they do not rotate, but rather have afixed relationship with the seal housing 25. This structure isrepresentative of many embodiments wherein the gel material 80 formsboth the zero seal 76 and instrument seal 78 but without the rollingcharacteristics associated with previous embodiments.

The embodiment of FIG. 43 is similar to that of FIG. 3 in that itincludes the two rollers 38 and 41 which were disposed in the sealhousing 25. In this embodiment, however, formation of the zero seal 76is facilitated with the addition of a third roller 216 which issupported on an arm 218 pivotally mounted on the seal housing 25. Thisroller 216 is operatively disposed distally of and in contact with therollers 38 and 41. In this position, the roller 216 forms a zero sealwith each of the rollers 38 and 41 in the absence of the instrument 30.When the instrument 30 is inserted, the instrument seal 78 is initiallyformed with the rollers 38 and 41. However, as the instrument 30 isinserted further, it contacts the roller 216 and pivots it away from theaxis 18. In this position, the roller 216 performs no sealing function.However, when the instrument 30 is removed, the arm 218 is biased tomove back to the operative position to facilitate formation of the zeroseal 76.

A similar embodiment is illustrated in FIG. 44 wherein the roller 216 issufficiently large to form the zero seal 76 with a pair of interiorwalls 221 and 223 which helped define the working channel 27. In thiscase, however, a septum 225 is provided to form the instrument seal 78.As the instrument 30 is inserted into the working channel 27, theinstrument seal 78 is formed with the septum 225. As the instrument 30is further inserted, it contacts the roller 216 and pivots the biasedarm 218 away from the working channel 27. As the instrument 30 isremoved, the zero seal 76 is established and the instrument seal 78 isbroken. Note that with the same cross-sectional view illustrated in FIG.44, the interior walls 221 and 223 may comprise a single cylindricalwall. In such an embodiment, the roller 216 preferably has a spiralconfiguration. Alternatively, the walls 221 and 223 may each have planarconfigurations in which case the roller 216 is preferably cylindrical inshape.

In the embodiment of FIG. 45, the zero seal is formed by two rollers,specifically the roller 216 carried by the biased arm 218, and a secondroller 227 carried by a biased arm 230. In this embodiment, the roller216 forms a seal with the interior wall 221 while the roller 227 forms aseal with the interior wall 223. A further seal 232 is required in thisembodiment between the roller 216 and 227. In this embodiment, the twowall seals and the further seal 232 combine to form the zero seal 76 inthe absence of the instrument 30. As in the previous embodiment, theinstrument seal 78 is formed by the septum 225.

The embodiment of FIG. 46 is similar to that of FIG. 3 in that itincludes the two rollers 38 and 41. However in this case, a pair oflevers 231 and 232 are individually pivotal on the housing 25 and biasedinto contact with the associated roller 38 and 41, respectively. Withthe levers 231 and 232, extending inwardly of the housing 25 and towardeach other, they are maintained generally in a closed positionillustrated in FIG. 46 but movable to an open position upon insertion ofthe instrument 30. With these operating characteristics, the leverage231 and 232 can aid several advantages to the present embodiment. In theclosed state, the levers 231 and 232 form pockets 233 which can be usedin the manner previously disclosed. As the instrument 30 is inserted,the levers 231 and 232 help guide it toward the intersection of therollers 38 and 41. If the instrument 30 has a sharp point, the levers231 and 232 will ensure that this point does not engage the rollers 38and 41 at a sharp angle. Rather, the sharp point of the instrument willcontact the rollers 38 and 41 only at a small acute angle facilitatingrotation of the rollers 38 and 41 and thereby inhibiting any damage tothe gel material 80.

FIG. 47 illustrates an embodiment wherein the working channel 27 islined with a tubular braid or mesh 234, at least within the seal housing25.

Accordingly, the mesh 234 extends between the rollers 38 and 41 andgreatly facilitates introduction of the instrument 30 centrally throughthe housing 25. In the absence of the instrument 30, the gel formingmaterial 80 forming the rollers 38 and 41 is sufficiently compliant toform the zero seal even with the mesh 234 present between the rollers38, 41. When the instrument 30 is inserted, the gel material 80 formsthe instrument seal 70 with the braid 234 and the instrument 30. Whenthe mesh 234 is made from a low-friction material, such as polyester, itnot only guides the instrument 30 centrally along the working channel27, but also reduces the insertion forces encountered by the instrument30.

Similarly braid material can also be used to form covers 236 and 238 onthe respective rollers 38 and 41 as shown in FIG. 48. Once again, itwill be noted that the compliance of the gel material 38 is sufficientto form both the zero seal 76 and the instrument seal 78,notwithstanding the presence of the mesh 236, 238 between the rollers38, 41.

The embodiment of FIG. 49 illustrates the seal housing 25 with therollers 38 and 41 disposed inside. In this case, the rollers 38, 41 aresized and configured to respond to distal pressure by moving proximallywithin the housing 25 to a proximal position as illustrated in FIG. 49.In this proximal position, the lateral seals 63 and 65 are formedbetween the housing 25 and the rollers 38 and 41, respectively. Theseseals, together with a further seal 241 formed between the rollers 48and 41 complete the zero seal 76. As the instrument 30 is inserted, thefree-floating rollers 38 and 41 are moved distally by the instrumentbreaking the zero seal 76 but at the same time forming the instrumentseal 78 with the instrument 30. This distal movement of the rollers 38and 41 is accomplished with the distal force of the instrument 30 whichacts against the proximal force of any distal pressure.

With respect to the embodiment of FIG. 49, it is contemplated that theinstrument 30 may be a pressurized injectate introduced into the workingchannel 27. To the extent the pressure of the injectate on the proximalside of the rollers 38, 41 exceeds the fluid pressure on the distal sideof the rollers 38, 41, the pressure differential will cause the rollers38, 41 to move distally, thereby creating a gap 243 through which theinjectate can pass between the rollers 38 and 41 as shown in FIG. 50.

Note that a pressure on a proximal side of the rollers 38, 41 has theopposite effect. To the extent that the pressure on the distal side ofthe rollers 38, 41 exceeds the pressure on the proximal side of therollers 38, 41, the pressure differential will cause the rollers 38, 41to move proximally into a more confined space, thereby creating a sealto inhibit proximal flow. Thus, with this embodiment, the devicefunctions as a one-way valve.

In another embodiment illustrated in FIG. 51, the rollers 38 and 41 areincluded in a roller assembly 244 which is carried by a catheter shaft245 and moved within a body conduit 247. The rollers 38, 41 are retainedwithin a rigid housing 250 in an orientation that is generallyperpendicular to the length of the shaft 245 and the conduit 247. Aballoon 252 is disposed around the housing 250 in order to reduce anytrauma to the body conduit 247. With this configuration, the gel rollers38, 41 and the balloon 252 seal the conduit 247 on either side of theroller assembly 244. Distal pressures from gases, liquids or solids canfacilitate an opening between the rollers 38 and 41 thereby permittingpassage to the proximate side of the roller assembly 244.

The embodiment of FIG. 51 would also facilitate insufflation of theconduit 247 distal of the roller assembly 245, while permitting passageof instrumentation into the insufflated conduit 247 without any loss ofgases or fluids.

Another embodiment, illustrated in FIG. 52 is also adapted for usewithin the body conduit 247. In this case, the rollers 38 and 41 arerotationally mounted on legs 253, which extend from the catheter shaft245. In the absence of any exterior housing, such as that designated bythe reference numeral 250 in FIG. 50, the gel rollers 38, 41 are free tocontact the conduit 247. Seals formed between the rollers 38 and 41 canfunction in the matter previously discussed.

It is also contemplated that the rollers 38 and 41 can be disposed in atransverse orientation within a lumen 254 of a tubular shaft 257 asillustrated in FIG. 53. In this case, the rollers 38 and 41 would bemounted on the axles 43 and 45, respectively, which are in turn carriedby the shaft 257. With this construction, the rollers 38 and 41 form thezero seal 76 across the lumen 254 of the shaft 257 but also accommodateintroduction of an instrument, such as a suture 256, along the lumen 254

The embodiment of FIG. 54 is most easily distinguished with reference tothe cross-sectional view of FIG. 55. In this embodiment, the sealmechanism within the seal housing 25 includes four rollers 258, 261,263, 265, with the rollers 258 and 263 mounted parallel to each other.The rollers 261 and 265 are mounted parallel to each other and angularlyspaced by 90 degrees from the rollers 258 and 263. The four rollers258-265 are formed of the gel material 80 in a preferred embodiment andcontact each of the two adjacent rollers along the working channel 27.Thus the rollers 258-265 can be disposed generally radially of the axis18. With this configuration, the relatively narrow rollers 258-265 canform seals with each other and thereby facilitate formation of both thezero seals 76 and instrument seals 78.

A further embodiment of the invention is illustrated in FIGS. 56-61.This is the same embodiment illustrated in multiple stages of operationwith different sizes of instruments. For example, the perspective viewof FIG. 56 and the top plan view of FIG. 59 illustrated this embodimentin the absence of the instrument 30. In this case, the embodimentincludes the cannula 16 and the seal housing 25 having a proximalopening 267 for receipt of the instrument 30. The seal housing 25 has agenerally triangular or trapezoidal configuration with a relativelynarrow proximal end 269, and a relatively wide distal end 270. Therollers 38 and 41 are mounted on post 272 and 274, respectively, whichare fixed to the walls of the housing 25 at the proximal end 269. Whenthe rollers 38 and 41 are disposed at the proximal end 269, the gelmaterial 80 tends to form the rollers 38, 41, concentrically around thepost 272 and 274, respectively.

As perhaps best illustrated in FIG. 59, the rollers 38 and 41 in thisnormal position not only form seals with the housing 25, but also formthe zero seal 76 with each other. When a relatively small instrument,such as that designated by the reference numeral 276 in FIGS. 57 and 60,is introduced through the opening 267, it tends to separate the rollers38 and 41 sufficiently to permit passage of the instrument. If theinstrument 276 is sufficiently small, the instrument seal 78 will beformed around the instrument 276 while it is still in the proximalposition.

For comparison, a larger instrument, designated by the reference numeral278 in FIGS. 58 and 61 can also be accommodated by this embodiment. Inthis case, the larger instrument 276 cannot be accommodated by therollers 38 and 41 in the proximal position. As a result, the instrument278 forces the rollers 38 and 41 to translate distally toward the widerdistal end 270 of the seal housing 25. With the additional widthprovided by the housing 25, the gel material 80 of the rollers 38 and 41can stretch on the post 272 and 274 respectively to accommodate thelarger instrument 278. In this stretch configuration, the rollers 38, 41form the instrument seal 78 with the larger instrument 278.

The stretching or translation of the rollers 38 and 41 can befacilitated by providing a low friction surface between the rollers 38,41 and the housing 25. In a preferred embodiment illustrated in FIG. 62,two endless loops, 281 and 283, are formed of a low-friction materialsuch as polytetrafluoroethylene. The loop 281 is mounted between posts283 and 285 which are fixed to the housing 25. With this structure, theloop 281 is disposed between the roller 38 and the housing 25.Similarly, the loop 283 is mounted to extend between posts 289 and 291between the roller 41 and the housing 25. As the larger instrument 278is inserted, the rollers 38 and 41 translate toward the wider distal end270 in the manner previously discussed. However, with the embodiment ofFIG. 66, the low-friction loops 281 and 283 significantly reducefrictional forces between the rollers 38 and 41 and the housing 25.This, of course, reduces the insertion forces associated with the largerinstrument 278.

From the foregoing embodiments, it would be apparent that the concept ofthe present invention may vary widely depending on the particularquality, characteristics and advantages desired for a given embodiment.For the most part, the concept will include at least one roller disposedwithin the seal housing of a trocar. The roller may not rotate, but inmost embodiments will either translate or rotate relative to the sealhousing. The roller will typically define at least a portion of theworking channel of the trocar and may operate relative to a wall oranother roller. The roller may be stationary or it may rotate relativeto a fixed or rotatable axle. Rotation of the roller will typicallyreduce insertion forces and protect the material of the roller. Braids,levers, and fixed walls can aid in defining the working channel.Multiple rollers may be used to define more than one working channel.Idler rollers and wiper seals can be used to find pockets for thereceipt of lubricants or antiseptic materials, for example. The rollerswill typically have a high level of compliance so that instrument sealscan be formed over a large range of instrument diameters. Inflatablerollers are contemplated but typically this compliance will be providedby a gel material offering a high degree of stretchability.

Due to the wide variation in embodiments included in this concept, oneis cautioned not to limit the concept only to the embodiments disclosed,but to determine the scope of the invention only with reference to thefollowing claims.

1. (canceled)
 2. A surgical access device comprising: a seal housing; aworking channel extending longitudinally through the seal housing; atleast one axle disposed in the seal housing and spaced from the workingchannel; and at least one roller mounted on and rotatable about the atleast one axle and in the presence of an instrument in the workingchannel defines an instrument seal.
 3. The surgical access device ofclaim 2 wherein the seal housing has a low friction coating in contactwith the at least one roller.
 4. The surgical access device of claim 2further comprising a low friction material disposed between the at leastone roller and the seal housing.
 5. The surgical access device of claim2 wherein the at least one roller is rotatable only about the at leastone axle and is only translatable proximally and distally.
 6. Thesurgical access device of claim 2 wherein the seal housing has an oblongrecess with a length parallel to the working channel and a widthperpendicular to the working channel, the length of the oblong recessbeing greater than the width of the oblong recess and wherein the atleast one axle is disposed in the oblong recess and the at least oneaxle is biased towards a proximal end of the oblong recess.
 7. Thesurgical access device of claim 2 wherein the at least one axlecomprises a first axle and a second axle and the at least one rollercomprises a first roller, the first roller being mounted on androtatable about the first and second axles.
 8. The surgical accessdevice of claim 2 wherein the at least one axle has an oblong shape. 9.The surgical access device of claim 2 wherein the seal housing has afirst recess and a second recess disposed within an inner surface of theseal housing and the seal housing having an inwardly extendingprotrusion disposed between the first and second recesses.
 10. Thesurgical access device of claim 2 wherein the at least one axle isdeformable along its length.
 11. The surgical access device of claim 10wherein the at least one axle comprises a spring.
 12. The surgicalaccess device of claim 2 wherein the seal housing comprises two entryports and one exit port.
 13. The surgical access device of claim 2further comprising a lever pivotably connected to the seal housing andbiased to contact the at least one roller.
 14. A surgical access devicecomprising: a seal housing; a working channel extending longitudinallythrough the seal housing; at least one axle disposed in the seal housingand spaced from the working channel; and at least one non-pivotableroller mounted on and rotatable about the at least one axle and in thepresence of an instrument in the working channel defines an instrumentseal, the at least one roller being made of gel material.
 15. Thesurgical access device of claim 14 wherein the at least one axle has anon-cylindrical shape and the gel material of the at least one rollerconforms to the non-cylindrical shape of the at least one axle.
 16. Thesurgical access device of claim 14 wherein the at least one axle isformed of a rigid plastic and the gel material is molded to the at leastone axle.
 17. The surgical access device of claim 14 wherein the gelmaterial of the at least one roller includes at least one groovebeginning at an outer surface of the gel material and extends inwardlytowards the at least one axle.
 18. The surgical access device of claim14 wherein the gel material of the at least one roller includes at leastone void between an outer surface of the gel material and the at leastone axle.
 19. The surgical access device of claim 14 wherein the gelmaterial of the at least one roller has an outer surface defined byalternating peaks and valleys.
 20. The surgical access device of claim14 wherein the at least one roller comprises a first roller and a secondroller and further comprising a tubular mesh extending between the firstand second rollers.
 21. A surgical access device comprising: a sealhousing; a working channel extending longitudinally through the sealhousing; at least one axle disposed in the seal housing and spaced fromthe working channel; and at least one roller mounted on and rotatableabout the at least one axle and in the absence of an instrument in theworking channel defines a zero seal.